Effects of land use intensity on the natural attenuation capacity of urban soils in Beijing, China

Abstract

Urban soils are major sinks that provide the services of attenuating and detoxifying environmental pollutants. This significant ecosystem service of urban soil can be evaluated by the natural attenuation capacity (NAC). In this research, we develop a method to calculate the natural pollutant attenuation capacity of urban soils on the basis of 5 chemical and physical measurements. By selecting municipal parks soils for reference, we assessed the spatial and temporal changes of NAC in Beijing city soils under influences of rapid urbanization. Results indicated that NAC was increasingly impacted by land use in the order: parks<schools<woods<residential areas<traffic areas. Sealed area rate and construction age are two main factors affecting the urban soil NAC. However, their roles are opposite. It would take dozens of years to reach the maximum soil NAC by soil self-recovery. The spatial distribution of NAC in Beijing built-up area resembled the age of urbanization. Regional hot spots of NAC corresponded to the land use distribution and the urbanization progress in Beijing city. The developed index can be used to assess the impacts of urbanization on soil ecosystem services of natural attenuation of contaminants.

Keywords: Ecosystem service; Natural attenuation; Soil quality mapping; Urban contaminated soil; Urban expansion.